The detection of atherosclerotic-related diseases in the early stages could
potentially impact medical treatment in a cost-effective manner. Atherosclerosis
is a common arterial disorder characterized by deposition of cholesterol,
lipids, and cellular debris in the inner layers of large- and medium-sized
arteries. As atherosclerotic deposition progresses, an area of narrowing, or
stenosis, forms, resulting in reduced circulation to organs and other tissues
supplied by the artery. When the stenoses become severe in critical arteries
(e.g., the carotids or the coronaries) the result can be a catastrophic stroke
or heart attack. In the early stages of the disease, the hemodynamics downstream
of a stenosis become disturbed. The resulting flow disturbances produce
characteristic features in Doppler ultrasound scans which are of diagnostic
value. A technique has been investigated for extracting the streamwise
turbulence intensity, or normalized velocity variance, using Doppler ultrasound
in an arterial flow model. The model consists of a pump and 1.3-cm i.d.
polyurethane tubing which is optically and acoustically transparent. Correlation
between Doppler ultrasound and laser Doppler anemometry (LDA) measurements was
examined in laminar as well as turbulent flow. Continuous flow has been employed
initially and the work will be extended to pulsatile flow to replicate cardiac
output.